Since most conventional crawlers used for transporting continuous-track vehicles are made from rubber material, a tension member, such as steel cords, Kevlar, etc., is inserted in the crawler body, so that it has stiffness and tensile strength sufficient not to be broken even during long time use.
The conventional method of inserting the tension member to the crawler includes an overlap method and an endless method.
According to the overlap method, regarding to FIG. 8 and FIG. 9, a plurality of tension members 10′ are arrayed in the direction of traversing the crawler at regular intervals with both ends thereof overlapped and adhered to each other, so that the tension members 10′ are supported by the adhering force. For the latter endless method, referring to FIG. 10 and FIG. 11, a single piece of the tension member 10′ is continuously wound in the direction of traversing the crawler without any severance or junction point.
As shown in FIG. 12, the crawler 1′ made by means of the overlap method and the endless method commonly forms a structure of the tension members inserted in the crawler body 2′ so that they form a single layer that the tension members are juxtaposed horizontally at regular intervals.
In FIG. 12, (A) shows a crawler in which a steel core 4′ is provided and (B) shows a crawler without a steel core.
The overlap method has an advantage that the manufacturing process is quite simple, but has disadvantages that, if the crawler is overloaded by the excessive external force, the adhered overlap portion may be broken and so the broken tension members may protrude outside, thereby the crawler being delaminated and cut. This deteriorates the durability of the crawler product.
To the contrary, the endless method has an advantage that the tension members are not easily broken or delaminated, since the method utilizes a single piece of tension member having no severed or junction point. However, it has disadvantages that manufacturing process is quite complicated and difficult, thereby increasing the costs and lowering the productivity.